Even if there was such a way (removing the .exe file from their computer would surely do) they would simply type in the url (www.cnet.com) in the address bar in Windows explorer and go browsing.
Some possibilities:
- You can use Content Advisor or the hosts file on their computer to block individual sites or certain rated sites, however.
- A variant: search for "Parental Control" software and see if any exists that let you block everything.
- Remove the TCP-IP software from Config Panel, network. But that only makes sense if you don't use it for the LAN (use NETBUIE for the LAN, for example, or Novell).
- Configure your own proxy server in the network, and find proxy software that can refuse access to clients based on ip-address (if such software exists).
Hope this helps.
Kees